The invention provides novel anthraquinone compositions that are useful as broad-spectrum quenchers of fluorescence and provides methods for making and using them. The anthraquinone quenchers can be conjugated to a variety of biologically relevant compounds, including lipids, nucleic acids, polypeptides,...http://www.google.com.au/patents/US8114979?utm_source=gb-gplus-sharePatent US8114979 - Di-alpha amino anthraquinone compositions
